This invention relates to a form-fill concrete wall and in particular to lock-together form that is fabricated from a light weight material. The material of the form preferably has certain advantageous characteristics, wherein the form is filled with concrete and the form becomes part of the resulting wall. Although permanent, in-place forms have be devised for concrete structures, it is generally required that these forms be erected around a preconstructed matrix of reinforcing steel. Such forms, with front and back shells, are tied together on each side of the erected reinforcing steel, after the steel rod has been tied together in a free standing lattice. While certain advantages of such construction are apparent, the set up time is not substantially less than for conventional concrete forming systems.
A prior art, snap-together form with fixed cross webs has been marketed. However, the fixed cross webs limit the use to a predefined wall thickness and horizontal reinforcing steel is difficult to install. Furthermore, the cross webs are fabricated from the same material as the shell. When a preferred plastic material is used for this shell, the plastic cross webs are structurally unacceptable.
The invented, in-place form system, has the advantage over conventional systems of enabling an outside sheath to encapsulate the concrete and to remain in-place after the concrete has set. The outside sheath can have either weather resistent qualities alone, or can have certain composition characteristics that make the sheathing ideal as an interior liner for containing liquid chemicals or granular minerals that may degrade the surface of conventional concrete. In this manner, a structure formed with the form as an outer sheathing forming the inside and outside wall surface can be utilized in waste treatment plants, chemical compounds, and retaining walls for minerals. For example, prilled elemental sulfur may generate local acid conditions on oxidation and result in a chemical reaction with calcium in cement. An acid resistent plastic sheathing would contain the sulfur prill without degradation of either the prill or the retaining wall.
A principle advantage in the proposed system, is that the form sheath can be erected using differently configured, and differently sized cross webs to enable walls of different thickness and height to be erected. In addition, the cross webs are designed to facilitate placement of horizontal reinforcing steel. Furthermore, the different configurations of the cross webs can provide for improved flow of the poured concrete through the webs in narrow walls. For maximized flow-through, the webs can be formed of segments of wire reinforcing mesh with hooked ends for connecting the two shells forming the sheath. The cross webs provide a support cradle for positioning horizontal bars of reinforcing steel at each desired height level. The cross webs are fabricated from structurally acceptable plate steel, tie-bar stock, or simply a reinforcing grade wire mesh. In this manner, the cross webs become an integral part of the internal reinforcement of the wall formed with the permanent outer sheathing.
The invented system allows for more flexibility than prior art systems and allows a form-fill wall to be constructed according to the structural requirements desired. The form-sheath system of this invention results in a permanent sheathed wall that has a variety of uses whether it be for housing, building construction, water tanks, lined lagoons, panel structures, or any of a variety of uses to which the construction is structurally suited.